Move internal modules to “internal” folder.

.internal/baseWhile.js

@@ -0,0 +1,25 @@
+import baseSlice from './.internal/baseSlice.js';
+
+/**
+ * The base implementation of methods like `dropWhile` and `takeWhile`.
+ *
+ * @private
+ * @param {Array} array The array to query.
+ * @param {Function} predicate The function invoked per iteration.
+ * @param {boolean} [isDrop] Specify dropping elements instead of taking them.
+ * @param {boolean} [fromRight] Specify iterating from right to left.
+ * @returns {Array} Returns the slice of `array`.
+ */
+function baseWhile(array, predicate, isDrop, fromRight) {
+  const length = array.length;
+  let index = fromRight ? length : -1;
+
+  while ((fromRight ? index-- : ++index < length) &&
+    predicate(array[index], index, array)) {}
+
+  return isDrop
+    ? baseSlice(array, (fromRight ? 0 : index), (fromRight ? index + 1 : length))
+    : baseSlice(array, (fromRight ? index + 1 : 0), (fromRight ? length : index));
+}
+
+export default baseWhile;